Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
  • C07D303/02—Compounds containing oxirane rings
  • C07D303/12—Compounds containing oxirane rings with hydrocarbon radicals, substituted by singly or doubly bound oxygen atoms
  • C07D303/18—Compounds containing oxirane rings with hydrocarbon radicals, substituted by singly or doubly bound oxygen atoms by etherified hydroxyl radicals
  • C07D303/20—Ethers with hydroxy compounds containing no oxirane rings
  • C07D303/22—Ethers with hydroxy compounds containing no oxirane rings with monohydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C317/00—Sulfones; Sulfoxides
  • C07C317/02—Sulfones; Sulfoxides having sulfone or sulfoxide groups bound to acyclic carbon atoms
  • C07C317/04—Sulfones; Sulfoxides having sulfone or sulfoxide groups bound to acyclic carbon atoms of an acyclic saturated carbon skeleton
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C381/00—Compounds containing carbon and sulfur and having functional groups not covered by groups C07C301/00 - C07C337/00
  • C07C381/12—Sulfonium compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D231/00—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings
  • C07D231/02—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings
  • C07D231/10—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
  • C07D231/12—Heterocyclic compounds containing 1,2-diazole or hydrogenated 1,2-diazole rings not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to ring carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
  • C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
  • C07D233/56—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D249/00—Heterocyclic compounds containing five-membered rings having three nitrogen atoms as the only ring hetero atoms
  • C07D249/02—Heterocyclic compounds containing five-membered rings having three nitrogen atoms as the only ring hetero atoms not condensed with other rings
  • C07D249/08—1,2,4-Triazoles; Hydrogenated 1,2,4-triazoles
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
  • C07D303/02—Compounds containing oxirane rings
  • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
  • C07D303/02—Compounds containing oxirane rings
  • C07D303/08—Compounds containing oxirane rings with hydrocarbon radicals, substituted by halogen atoms, nitro radicals or nitroso radicals

Definitions

• This invention relates to the preparation of epoxides from carbonyl compounds using either trimethylsulphonium hydrogen sulphate and/or bis(trimethylsulphoniu ) sulphate or trimethylsulphoxonium hydrogen sulphate and/or bis(trimethylsulphoxonium) sulphate. It also relates to trimethylsulphonium hydrogen sulphate, trimethylsulphoxonium hydrogen sulphate and bis(trimethylsulphoxonium) sulphate, which are novel compounds, and to processes for their preparation.
• the invention further relates to processes for preparation of sulphonium ylide, (CH,) 2 S + - ⁇ CH 2 and sulphoxonium ylide, (CH-) 2 S + (0)- ⁇ CH 2 using these intermediates and a process for the preparation of fungicides and insecticides using these intermediates.
• a disadvantage of the known process is that organic material, in the form of an alkali metal methylsulphate, is present in the effluent. As well as being environmentally undesirable, methylating agent is lost and this is chemically inefficient. A further disadvantage is that dimethyl sulphate is a carcinogen.
• a process for transforming a carbonyl compound into its corresponding epoxide which comprises contacting the carbonyl compound with either trimethylsulphonium hydrogen sulphate and/or bis(trimethylsulphonium) sulphate or trimethylsulphoxonium hydrogen sulphate and/or bis(trimethylsulphoxonium) sulphate, in the presence of a base.
• the compounds, trimethylsulphonium hydrogen sulphate having the formula: (CH.,).,S + .HS0, ⁇ , trimethylsulphoxonium hydrogen sulphate having the formula: (CH 3 ) ⁇ S(0).HS0, , and bis(trimethylsulphoxonium) sulphate having the formula: ((CH ⁇ ),S(0).) 2 S0, , are novel and form another aspect of the present invention.
• the compound, trimethylsulphonium hydrogen sulphate, is a novel compound. Although it is mentioned by name in Czechoslovakian Patent No 254,032, no method or reference is given for its preparation.
• a process for preparing trimethylsulphonium hydrogen sulphate which comprises reacting together di ethylsulphide, methanol and sulphuric acid at a temperature of from -20°C to +100°C (in a sealed system) or from -20°C to +40°C (at atmospheric pressure).
• dimethylsulphide normally about 2 moles
• sulphuric acid normally from 1 to 2 moles
• the methanol is added slowly, for example dropwise, to a molar excess of dimethyl sulphide, for instance, 2 moles of dimethyl sulphide for each mole of methanol used in the reaction, at a temperature preferably below 25 ⁇ C, when the reaction is carried out at atmospheric pressure.
• Concentrated sulphuric acid such as commercially available 98X sulphuric acid solution, may then be added gradually to the stirred mixture maintaining the temperature below 25°C.
• the time taken for the reaction will depend inter alia on its scale. Where half a mole of methanol (i.e. 16g) is used, the methanol addition is completed typically in about ten minutes, and the sulphuric acid addition in about twenty minutes.
• the methanol may be added to a mixture of the sulphuric acid and dimethyl sulphide. The reaction mixture may be stirred for several hours at ambient temperature before use.
• trimethylsulphonium hydrogen sulphate is prepared by a process which comprises reacting together dimethyl sulphide, trimethylsulphonium methyl sulphate and sulphuric acid at temperature of from -20°C to +100°C (in a sealed system) or from -20°C to +40°C (at atmospheric pressure).
• This reaction is conveniently carried out by adding a molar excess of dimethyl sulphide, for example, 2 moles of dimethyl sulphide for each mole of trimethylsulphonium methyl sulphate used in the reaction, to an aqueous solution of trimethylsulphonium methyl sulphate and then adding gradually to the mixture about 2 moles of concentrated sulphuric acid, such as 98% sulphuric acid.
• the reaction mixture is then heated to about 40°C, when the reaction is carried out at atmospheric pressure, and stirred for several hours until reaction is complete.
• Trimethylsulphonium methyl sulphate is a known compound and may be prepared by the reaction of dimethyl sulphide and dimethyl sulphate.
• trimethylsulphonium hydrogen sulphate is prepared by a process which comprises reacting together a trimethylsulphonium halide, sulphuric acid and hydrogen peroxide at a temperature of from 0°C to 100°C.
• Trimethylsulphoxonium hydrogen sulphate can also be prepared using this process therefore, according to a further aspect of the present invention there is provided a process for preparing trimethylsulphoxonium hydrogen sulphate which comprises reacting together trimethylsulphoxonium halide, sulphuric acid and hydrogen peroxide at a temperature of from 0°C to 100°C.
• This reaction is conveniently carried out by adding, with stirring, an aqueous mixture of about one mole of concentrated sulphuric acid, such as 98% sulphuric acid, and about a half mole of hydrogen peroxide, such as 30% hydrogen peroxide, to one mole of, for example, trimethylsulphonium iodide, in the presence of an inert, water immiscible, iodine-extracting solvent, such as carbon tetrachloride, in this case to remove iodine produced during the reaction.
• an inert, water immiscible, iodine-extracting solvent such as carbon tetrachloride
• the liberated chlorine can be removed using a sodium hydroxide scrubber, suitably with an inert gas flow.
• either a bromine-extracting solvent or scrubber can be used.
• the trimethylsulphonium hydrogen sulphate so formed can be isolated from the aqueous phase by evaporation after the unreacted peroxide has been destroyed by the addition of, for example, palladium on carbon.
• the trimethylsulphonium halide in this preparation can be replaced by trimethylsulphoxonium halide for the preparation of trimethylsulphoxonium hydrogen sulphate.
• Trimethylsulphonium and trimethylsulphoxonium halides are readily prepared using processes known in the art, for example, Organic Chemistry of Sulfur, pages 474-475, edited by S. Oae, 1977; uhn and Trischmann, Annales 611, page 117, (1958).
• the invention further includes the products obtained by the processes of the invention.
• a process for preparing sulphonium ylide (CH,) 2 S + - ⁇ CH 2 using trimethylsulphonium hydrogen sulphate which comprises either (a) reacting together dimethyl sulphide, methanol and sulphuric acid at a temperature of from -20°C to +100°C (in a sealed system) or from -20°C to +40 ⁇ C (at atmospheric pressure); or (b) reacting together dimethyl sulphide, trimethylsulphonium methyl sulphate and sulphuric acid at a temperature of from -20°C to +100°C (in a sealed system) or from -20°C to +40°C (at atmospheric pressure); or (c) reacting together a trimethylsulphonium halide, sulphuric acid and hydrogen peroxide at a temperature of from 0°C to 100°C; and basification of the trimethyl ⁇ sulphonium hydrogen sulphate formed.
• a process for preparing sulphoxonium ylide (CH,) 2 S (0)- ⁇ CH 2 using trimethylsulphoxonium hydrogen sulphate which comprises reacting together a trimethylsulphoxonium halide, sulphuric acid and hydrogen peroxide at.a temperature of from 0°C to 100°C and basification of the trimethylsulphoxonium hydrogen sulphate formed.
• the bis(trimethylsulphonium) sulphate which may also be used in the epoxidation process, either alone or in combination with trimethylsulphonium hydrogen sulphate is a known compound and may be prepared as described in Z.Kris allog., 147(3-4), 319-25. It is not, however, known that it can be used for the preparation of epoxides.
• Both the bis(trimethylsulphoxonium) sulphate, which may be used in the epoxidation process either alone or in combination with trimethyl ⁇ sulphoxonium hydrogen sulphate, and the bis(trimethylsulphonium) sulphate, which may be used in the epoxidation process either alone or in combination with trimethylsulphonium hydrogen sulphate, may occur as impurities during preparation of their respective mono salts.
• the base is suitably a strong base, for example, an alkali metal hydroxide, such as sodium or potassium hydroxide. Potassium hydroxide flake is particularly convenient to use.
• an alkali metal hydroxide such as sodium or potassium hydroxide.
• Potassium hydroxide flake is particularly convenient to use.
• 1 to 2 moles of trimethylsulphonium hydrogen sulphate preferably 1 to 1.2 moles, are used for each mole of carbonyl compound, with typically 1 to 20 moles, preferably 1 to 8 moles of base.
• the progress of reaction may be monitored by analysing samples taken at intervals using chromatographic methods and the reaction continued until adjudged complete.
• the epoxide may be recovered from the reaction mixture by adding water to the mixture, filtering off any residual inorganic salts, distilling off excess dimethyl sulphide and any solvent, such as dichloromethane, used to wash the filtered residues and separating the product as an oil from the aqueous layer.
• Trimethylsulphonium hydrogen sulphate can be substituted in the above epoxidation reaction by bis(trimethylsulphonium) sulphate or trimethylsulphoxonium hydrogen sulphate and/or bis(trimethylsulphoxonium) sulphate using the same or similar reaction conditions.
• the base can be aqueous or non-aqueous.
• Aqueous reaction conditions are described in Journal of Organic Chemistry 34, No 7, p2133, 1969.
• the reaction can also be carried out using a phase transfer catatyst, such as quaternary ammonium salts, for example, benzyl triethyl ammonium chloride. Suitable conditions for such reactions are given in Indian Patent No. 155768.
• the process for preparing the epoxide is believed to proceed via the sulphonium ylide, (CH ⁇ ) 2 S + - ⁇ CH 2 , which is formed on basification of the trimethylsulphonium hydrogen sulphate, or via the sulphoxonium ylide (CH 3 ) 2 S + (0)- ⁇ CH 2 , which is formed on basification of the trimethyl ⁇ sulphoxonium hydrogen sulphate.
• CH ⁇ sulphonium ylide
• CH 3 sulphoxonium ylide
• the invention is, therefore, applicable to any carbonyl compound which can be transformed into its corresponding epoxide by the sulphonium ylide (CH,) 2 S + - ⁇ CH 2 or sulphoxonium ylide (CH ⁇ ) 2 S + (0)- ⁇ CE .
• This includes any aldehyde or ketone whose transformation to the corresponding epoxide via the sulphonium ylide or sulphoxonium ylide is described in the literature.
• R is H, C._ 6 alkyl, C «_, haloalkyl, C, 6 cycloalkyl, C, , cycloalkyl(C- ,)alkyl, optionally substituted phenyl or optionally substituted benzyl; or R. and R join together to form a C 5 _ 7 cycloalkyl ring.
• halogen is preferably fluorine, chlorine or bromine.
• substituted substituents which may be present in phenyl groups include one or more of halogen (especially chlorine and fluorine),
• R is n- or jt-butyl, trifluoromethyl or phenyl, and R is phenyl or benzyl, the phenyl groups and the phenyl moiety of the benzyl group being optionally substituted with fluorine and/or chlorine in the 2- and/or
• ketones which are of particular interest are:
• ketones are transformed into epoxides of the formula (II) in
• the invention provides a process for transforming an aldehyde or ketone into its corresponding epoxide, which comprises either:
• step (d) reacting together a trimethylsulphoxonium halide, sulphuric acid and hydrogen peroxide at a temperature of from 0 ⁇ C to 100°C; and contacting the aldehyde or ketone with the product obtained from step (a), (b), (c) or (d) in the presence of a base.
• the epoxides obtained by the invention may be useful products in their own right or may be used as intermediates for further processing.
• the epoxides of formula (II), defined above, may be used to
• R is C. , alkyl, C. , haloalkyl, C- 6 cycloalkyl, C, , cycloalkyl(C- ,)alkyl or optionally substituted phenyl; R is H, C- , alkyl, C, , haloalkyl, C, , cycloalkyl,
• fungicides of formula (III) of interest are l-(2-fluorophenyl)-l-(4-fluorophenyl)-l-H-l,2,4-triazole-l-ethanol, l-n-butyl-l-(2,4-dichlorophenyl)-lH-l,2,4-triazole-l-ethanol and those compounds disclosed in EP 15756-A.
• 1 2 epoxide are those of formula (I) where R is C. , haloalkyl and R is optionally substituted phenyl.
• the halogen is preferably fluorine or chlorine, and substituents which may be present in the phenyl group include one or more of halogen (especially chlorine, bromine or fluorine), C. , alkyl (especially methyl and ethyl), C- , haloalkyl (especially trifluoromethyl), C * , alkoxy (especially methoxy and ethoxy), C. , haloalkoxy (especially trifluoromethoxy and difluoromethoxy), nitro and phenoxy.
• R1 is trifluoromethyl and R2 is phenyl optionally substituted with methoxy or ethoxy in the 4-position and optionally fluorine in the 3- and
• ketones which are of particular interest are p-ethoxytrifluoro-acetophenone, p-methoxytrifluoro
• GC gas chromatography
• NHR nuclear magnetic resonance
• s singlet
• m multiplet
• g grammes
• ml millilitres
• THF - tetrahydrofuran
• NHR data are selective.
• Chemical shifts ( ⁇ ) are measured in parts per million from THS or DSS, and CDC1 ⁇ or fully deuterated DMSO were used as solvents.
• Trimethylsulphonium iodide (9.8g, 0.048 moles) was dissolved in water
• the aqueous layer of the reaction mixture (prior to its use in the epoxidation reaction) contained a mixture of sulphuric acid and hydrogen sulphate ions (HS0, ⁇ ).
• Silver sulphate (7.0g, 0.022 mole) was dissolved in water (1200ml) at room temperature.
• Trimethylsulphonium iodide (9.16g, 0.045 mole) was dissolved in water (50 ml) and added to the stirred silver sulphate solution.
• the reaction mixture was stirred for 3 hours at room temperature during which time a solid (silver iodide) was precipitated. This solid was filtered off and the filtrates concentrated under reduced pressure to leave a grey solid.
• the grey solid was slurried in methanol and insoluble material removed by filtration. The methanol filtrates were concentrated under reduced pressure to leave a white solid.
• the NHR characteristics of the authentic sample are: HNMR (CDC1,, TMS): ⁇ 0.5-2.4 (m, 9H, (CH 2 ) 3 CH 3 ); 2.6-3.0 ( , 2H, CH 2 0), 7.0-7.5 (m, 6H, aromatic H).
• reaction mixture was added to water (600ml) and extracted with pentane (5 x 20ml).
• pentane extracts were combined and the solvent removed under reduced pressure to give a yellow oil.
• the oil was distilled under reduced pressure (7mm Hg, still head temperature 64-65°C) to give a clear colourless oil, (10.6g, 55% yield of theory).
• the aqueous layer was washed with carbon tetrachloride (2 x 500mls) and iodine was still being extracted. Therefore, carbon tetrachloride (600 ml) was added to the aqueous layer, stirred for one hour and the layers separated. Further washing of the aqueous layer with carbon tetrachloride (50ml) showed no colour change indicating that the iodine had been completely extracted.
• the aqueous layer was washed with ether (50ml) and sodium metabisulphite (0.2g) was added to destroy any residual hydrogen peroxide.
• Bis(trimethylsulphoniura)sulphate (0.85g, 3.4 mmole) (prepared by the method described in Example 3) was added to dimethylsulphide (0.43g, 6.9 mmole) and t-butanol (0.15g, 2 mmole).
• Water (0.12g, 7 mmole) and l-(2,4-dichlorophenyl)-n-pentan-l-one (1.57g at 95.5%, 6.5 mmole) were added and the mixture stirred vigorously.
• Potassium hydroxide flake (1.07g at 95%, 18 mmole) was then added and the mixture stirred at ambient temperature for 50 hours.
• EXAMPLE 12 Preparation of l-(2,4-dichlorophenyl)-l-n-butyl oxirane. Methanol (13.4g, 0.419 moles) was added dropwise over 10 minutes to dimethylsulphide (52.lg, 0.841 moles) while maintaining the temperature below 25°C. Sulphuric acid (46.2g at 98%, 0.462 moles) was added to the stirred mixture over 30 minutes maintaining the temperature below 25°C. The reaction mixture was stirred ovenight at room temperature.
• benzaldehyde (13.52g at 98%, 0.125 moles), toluene (92g, 1 mole), and n-propanol (35.5g, 0.59 moles) and the mixture stirred and heated to 50°C.
• Aqueous sodium hydroxide solution (32g at 53%, 0.425 moles) was added and a temperature rise to 80°C was observed (due to neutralisation of excess acid).
• the mixture was cooled to 70 ⁇ C and stirred at this temperature for 1 hour.
• the mixture was cooled, the organic layer separated, washed with water and dried over magnesium sulphate.
• Qualitative GC analysis showed 76% conversion to the title epoxide (by comparison with authentic sample).
• EXAMPLE 15 Preparation of l-(2,4-dichlorophenyl)-l-n-butyloxirane Sulphuric acid (18.75g at 98%, 0.187 moles) was added dropwise over 60 minutes, with stirring, to dimethyl sulphide, (15.8g at 98%, 0.25 moles) while maintaining the temperature below 25 ⁇ C. Methanol (4.0g, 0.125 moles) was slowly added to the stirred mixture maintaining the temperature below 30°C. The reaction mixture was stirred for -Vh hours.
• dichloromethane (53.5g, 0.63 moles), l-(2,4-dichlorophenyl)-n-pentan-l-one (19.35g at 95.5%, 0.08 moles) and benzyltriethyl ammonium chloride (0.82g, 0.0036 moles).
• Aqueous sodium hydroxide solution (46.3g, 1.16 moles NaOH in 32g water) was added to the mixture and stirred for 20 hours at room temperature. Water (350ml) was added and the layers allowed to settle. The organic layer was separated and the aqueous layer extracted with dichloromethane (4 x 50ml). The organic extracts were combined and washed with water until a neutral pH was obtained. The organic layer was then dried over anhydrous sodium sulphate and solvent removed under reduced pressure to yield an oil (20.6g) at 84.8%, i.e. 89% of theory, by comparison with the authentic sample given in Example 4).
• the reaction mixture was added to water (to dissolve any inorganic material) and extracted with dichloromethane.
• the dichloromethane layer was separated and the solvent removed under reduced pressure to give an oil (24.3g at 91.6%, i.e. 90.8 % yield of theory, by comparison with the authentic sample given in Example 4).
• EXAMPLE 17 Preparation of l-(2,4-dichlorophenyl)-l-n-butyloxirane Sulphuric acid (21.2g at 98%, 0.212 moles) was added dropwise with stirring to dimethylsulphide (16.4g at 98%, 0.26 moles) over a period of time maintaining the temperature below 25°C. Methanol (4.0g, 0.125 moles) was added slowly to the stirred mixture, maintaining the temperature below 30°C. The reaction mixture was stirred at 25°C for 4% hours and held unagitated overnight at room temperature.
• Potassium hydroxide flake (34.8g, 0.59 moles) was added in ten aliquots over 3 hours and the mixture then stirred at room temperature overnight.
• the reaction mixture was added to water (to dissolve an inorganic material) and extracted with dichloromethane.
• the dichloromethane layer was separated and the solvent removed under reduced pressure to give an oil (22.7g at 87.7%, 81.2% yield of theory, by GC comparison with authentic sample).

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